1. Field of the Invention
The present invention relates to a pressure sensitive adhesive which can be used to join textile materials together creating a durable wash resistant bond. This adhesive can be used in place of the normally more durable heat activated adhesives such as thermoplastic powders, films or tapes which require heat above room temperatures to flow the adhesives between textile materials which are desired to be joined and then allowed to cool to create a durable bond. The invention described could also replace sewing or stitching of seams to join textile materials together. The product could be utilized to join a broad range of products including but not limited to; garment assembly specifically seams, adhering decorative textile transfers, emblems and appliques that may be applied to a variety of different textile substrates, including apparel, headwear, accessories, textile crafts, luggage and or home furnishings. The particular adhesive is suited for bonding natural fibers such as cotton, silk and cellulosic such as rayon as well as synthetic fiber like polyester and blends thereof.
2. Description of the Background
Apparel and accessory manufacturers use various methods to construct garments and apply decoration and identification to garments and textiles. Common technologies include sewing, heat-sealing tapes or adhesives, sonic welding, direct embroidery and heat activated transfer.
Various methods are used for joining textile products together and for applying decoration and identification to textile materials. Sewing is most commonly used to join fabrics together and for attaching decorative elements. This process is both machinery and labor intensive
Direct embroidery is typically performed by a machine that applies stitching of various colors and styles directly onto fabric to create a design. Embroidered designs have a much greater aesthetic value, and stand repeated home and industrial launderings. However, direct embroidery remains a complex, expensive and time-consuming process as well. Emblems are discrete items containing decoration which are manufactured separately and post-applied by various means such as sewing or heat-seal adhesives to textile articles, obviating some of the disadvantages of direct embroidery.
Sonic welding is another method used to apply decoration and identification to garments and textiles. This process requires the creation of unique, expensive special dies for any design to be applied. Sonic welding allows texturing, but also requires chemical compounds that some companies find unacceptable, and that can result in a product that does not stand stretching or repeated home and industrial laundering. Consequently, embroidery has instead become the primary method for applying decoration and identification in the industry.
Up until now the methods used for permanently attaching fabric to fabric or decorations to fabric have required sewing which is time consumptive and to be performed economically requires machinery and skilled operators. Another method of permanently adhering textiles to textiles is through the application of heat to activate a thermoplastic adhesive which also requires equipment. While these methods create durable washable bonding they are impractical for quickly bonding textile products together without equipment. A quick and easy method which can safely be used by consumers of all ages, including children or by industry to bond textile materials or decorations together without equipment is desired.
There have been a few attempts at providing emblems via thermal application. U.S. Pat. No. 5,009,943 to Stahl discloses a method for producing a multi-colored emblem that may be ironed-on to garments to provide an embroidered appearance. This method entails laminating a material blank, cutting the laminated material to a specific design, embroidering about the periphery of the cut design, laminating the assembly onto a second material blank, and coating the underside with a thermal adhesive layer. The emblem can then be heat-sealed to a garment. Despite the ability to give a realistic embroidered look, thermally-bonded emblems still require additional processing steps and equipment to heat the emblem at application. In addition, thermal transfers typically have a greater rigidity or stiffness compared to the product to which they are being adhered. When applied, such emblems can decrease the comfort to the wearer of an apparel garment and change the drape characteristics of the product making it less visually appealing.
The apparel industry is gravitating toward quick-change low-inventory production, but the labor, inventory, and other costs associated with the foregoing techniques make them relatively slow and expensive. Consequently, embroiderers and other apparel customizers using these techniques typically require substantial minimum-quantity orders, and bulk orders are only justified where economics warrant the expenditure associated with sewn-in decorations or heat-sealing them onto products. Apparel manufacturers would much prefer to customize articles in small batches in order to keep turnaround time and inventory at a minimum. For smaller quantity orders, however, sewing and heat-sealing decorations onto apparel, home furnishings or luggage is costly and time consuming and often requires specialized equipment and skilled operators. Individual consumers attempting to bond textile products including emblems, badges, indicia and other forms of textile embellishments, together must set-up to sew these items by hand or with a machine requiring at a minimum a needle and thread or use a home iron to activate a thermal adhesive for that purpose. These steps make the application location and equipment dependent and cause safety concerns if children participate in the process. Thus customization and personalization of textile products by consumers is limited by equipment, location and safety concerns. In a commercial environment industrial sewing equipment or heat presses would be necessary to set up and operate in production to decorate textile based items. In addition, the manufacture of heat applied bonding such as seams, appliques and emblems requires special equipment to apply the adhesive to the base layer. Much of the production overhead required with the foregoing processes could be avoided with a room temperature transfer pressure sensitive adhesive fabric, applique or applied emblem. However, there have been comparatively few attempts to provide room temperature transfer emblems because the bond quality has in the past not been able to withstand wear and laundering.
For example, U.S. Pat. No. 5,635,001 to Mahn, Jr. issued Jun. 3, 1997 shows cloth transfers that include a cloth layer coated with a plastic layer which is, in turn, coated with a pressure sensitive adhesive layer. The pressure sensitive layer as described is for pre-positioning a decoration prior to sewing or alternatively heat-sealing with an adhesive and is not proposed as a stand-alone method to create a permanent bond between textile products.
U.S. Patent Application 20030023018 by Nakano et al. issued Jan. 30, 2003 shows an acrylic pressure-sensitive adhesive which has a weight average molecular weight of 1,200,000 or higher and in which the proportion of components having a molecular weight of 100,000 or lower is 10% by weight or lower based on the weight of the whole polymer. This results in a uniformly-viscous acrylic adhesive less apt to foul an extruder. The adhesive claimed here is targeted for application in tapes, labels and sheets with no mention of textile-to-textile applications or launder ability.
U.S. Pat. No. 6,582,791 to Peloquin et al. issued Jun. 24, 2003 shows a pressure sensitive adhesives for use on low energy surfaces designed to achieve high or permanent adhesion. This patent suggests the addition of various additives to an acrylic base polymer such as a tackifier, for better adhesion of vinyl film to low surface energy substrates and makes no claims related to textile to textile application or launder ability.
U.S. Pat. No. 6,753,050 to Dalvey et al. issued Jun. 22, 2004 shows a cold image transfer sheet for T-shirts including an image imparting layer and an adhesive layer. The adhesive layer permits transfer of an image to a substrate. The image transfer sheet comprises a base layer 12 (FIG. 1), a release layer 14 that overlays the base layer, a pressure-sensitive adhesive layer 16 (a variety are suggested including acrylic-based), and a polymer layer 18. An image or a portion of an image is imparted to one or more of the adhesive layer 16, polymer layer 18, primer layer 20 or optional second ink-receiving layer 22. The image transfer sheet described is a thin polymer film between 0.2 to 3 mils in thickness. The PSA described is non-specific and wash characteristics and launder ability are not described. The patent claim also does not address textile to textile applications.
U.S. Pat. No. 4,880,678 to Goffi issued Nov. 14, 1989 shows a dry-cold transfer sheet suited for application to wood, that comprises a colored film adhering to a backing sheet with an interposition of a layer of release varnish. The colored film included 30-40% pigment, 1-4% of cycloaliphatic epoxy resin, from 15-35% of vinyl copolymer, from 1-4% of polyethylene wax. This Dry Transfer sheet consists of a colored film for application to wood panels. Again the reference does not apply to textiles and survivability to laundering.
U.S. Pat. No. 6,951,671 to Mukherjee et al. (P. H. Glatfelter Company) issued Oct. 4, 2005 shows an ink jet printable heat transfer material with cold release properties. The invention consists of multiple layers of coatings applied to a suitable substrate, typically paper. The first optional layer coating consists typically of a pigmented coating bound together with a synthetic or natural binder and is applied in sufficient quantity to level and densify the surface of a given substrate. The second coating is applied over the first and consists of a silicone coating with a controlled surface energy. The surface energy must be such that the subsequent aqueous coatings can be applied over top with good wetting and adhesion, but low enough for an easy removal from the heat transfer after cooling. A third or wash layer is applied over the silicone release layer so the coating does not come off during subsequent coating passes and during handling by the user. The wash layer consists of one or more thermoplastic polymers including ethylene acrylic acid, waxes, and other polymers along with dispersions of non-water soluble plasticizers and antioxidants. As described heat is require to bond a composite of paper and silicone and non-water soluble plasticizers onto a substrate. Although the application here is to fabric and discusses washing it does not teach bonding one textile-based product to another, nor is it specific in the composition of the pressure sensitive adhesive and the durability of the bond to laundering.
Though sewing and stitched embroidery are avoided in all of the foregoing cases to initially bond products, the resulting products cited above are inferior in durability and cannot withstand repeated washing or require additional process steps of sewing or heat-sealing. It would be greatly advantageous to consumers and industry to provide a method for adhesively bonding textile products, appliques, emblems and other textile-based brand identification or fabrics to apparel and or accessories, headwear, crafts, home furnishings and luggage which requires no minimum quantity, no equipment, and which is less time consuming and labor intensive than affixing by sewing or heat-sealing. Importantly, the bonding can occur quickly, where this activity can be performed safely by both adults and children.